1. Field of the Invention
This invention relates to an emergency signalling apparatus to be used by persons needing rescue. In particular the invention relates to a device for locating lost persons.
2. Description of the Related Art
Often when a person is lost, they are lost in an environment that makes it difficult for rescuers to find the person. For example, the environment can be a wooded or a forested area. Even in the case of a deforested area such as a desert, it can be difficult to spot a person who is lost. The delay in finding a lost person can be even more critical when the person has been injured. In that situation it is critical that the person be found as quickly as possible and given medical help. There are many other situations requiring search and rescue, including, for example, a boat adrift at sea due to engine failure or being out of fuel.
In the prior art, there are a number of search and recovery devices that include a deflated balloon which can be inflated by pressurized lighter than air gas carried in a cartridge. When the gas in the cartridge inflates the balloon, the balloon rises to a height observable by rescuers. Such a search and recovery device is described in U.S. Pat. No. 3,874,325, issued Apr. 1, 1975. In another emergency locating device, described in U.S. Pat. No. 3,941,079 issued Mar. 2, 1976, a reel is attached to a gas cylinder for inflating a balloon. The reel has a tether line disposed thereon and attached to the balloon. This device has the disadvantage that the reel adds weight and volume to the device.
U.S. Pat. No. 4,013,035 issued Mar. 22, 1977 describes a balloon signal assembly that includes an inflatable balloon capable of retaining a lighter than air gas connected to a container of gas under pressure. A needle is connected to the container for breaking the seal between the pressurized gas inside the container and the balloon, so that the balloon inflates. A disadvantage of this and similar devices is that a complicated valve assembly such as a needle connected to the container is required in order to provide a mechanism for breaking the seal between the pressurized container and the balloon. Some assemblies also have a valve which is provided to prevent re-entry of the gas from the balloon into the container. These complex assemblies add weight and raise the cost of the devices.